Sex-determining Region Y gene
Y chromosome is the male chromosome of mammals, including humans, and other animals. It bears genes that are passed on from the father to the son or male offspring. It has genes for sex determination as well as other genes, such as those that code for zinc finger protein, acetylserotonin methyltransferase, amelogenin, and transcription factor SOX-21. One of the genes that are involved in sex determination is the sex-determining Region Y (SRY) gene. It is the gene that codes for the protein, sex-determining region Y (SRY) protein (also called testis-determining factor). This gene is located on the sex-determining region of the Y chromosome. In particular, it is found in the chromosome band Yp11.3. It encodes for a transcription factor which belongs to the high mobility group-box family of DNA-binding proteins. The SRY protein is the one responsible for the initiation of male sex determination.1 When this protein is absent, the testicular development becomes defective. This is seen in individuals with a male karyotype, i.e. XY chromosomes. Having sex chromosomes comprised of X and Y chromosomes but lacking the SRY gene leads to a condition called Swyer syndrome. The individual has female phenotype despite the presence of Y chromosome. A possible cause of the lack of SRY gene is due to an atypical genetic recombination during crossover in meiosis. Normally, the SRY gene stays on the Y chromosome. However, when the SRY gene is transferred to the X chromosome during crossover the resulting Y chromosome would no longer have the SRY gene. The paternal X chromosome containing the SRY gene, in turn, may produce offspring with an XX female karyotype and with the possibly of manifesting male characteristics (i.e. testis). This condition is called XX male syndrome.
- SRY gene
1 Berta, P., Hawkins, J. R., Sinclair, A. H., Taylor, A., Griffiths, B. L., Goodfellow, P. N., and Fellous, M. (November 1990). "Genetic evidence equating SRY and the testis-determining factor". Nature. 348 (6300): 448–50.